1984 9.9 Evinrude Forward Gear Issue

[Fishon72]

Hello,

Running a 1984 9.9 Evinrude on a 15’ Starcraft. A couple weeks ago while running on plane (10.5 mph) with myself (230 lbs) in the back of the boat and my Dad (200ish lbs) up front I noticed a jerky feeling in the motor every minute or so. Eventually the motor seemed to pop out of gear, as it revved very high and did not immediately come down when I throttled back. I’m a bit of a panic I shut it off while it was still in forward, and had a bit of a time getting it back into neutral and started again.
Next trip, I was by myself, forgot to weigh the bow down, and couldn’t get on plane but otherwise the motor ran without a hiccup so I thought maybe I hit something.
Hit the lake with my wife and son this week (roughly 200 lbs up front) and the motor started off running beautifully on plane for about 10 minutes, then out of nowhere it revved very high as the boat came to a stop. This time I put the gear in neutral as I tried to throttle down, but it seemed to rev pretty high for several seconds before it knocked violently and then went back to running normal in neutral. Limped back to the dock about 5 mph without an issue.
I went out by myself after that with the bow weighed down with a 45 lb bumper plate and the boat planed (12.5 mph) and I couldn’t duplicate the issue after about 20 minutes of full throttle.
I assumed spun prop hub so I bought a new prop, which I haven’t tested yet. Issue is I also checked the gear case oil and it is extremely cloudy green (almost an olive drab color) with a small amount of very tiny metal flecks in it. I didn’t change the oil when I bought the motor, but the seller told me he was a mechanic and had done it in the spring. Is a very small amount of metal particulates in the oil normal, or is this indicative of a gear issue? I was going to just change the oil and see what happens, but don’t want to damage anything beyond the gears if that sounds like the issue.

Sorry for the long post, thanks in advance!

-Jay

 

[Pappy]

Well the good news on this is that a failed gear issue will not come and go. Usually quite a bit of metal in the gear oil as well.
You can mark a prop and hub with a paint pen and see if the hub is spinning pretty easily then take it out and duplicate your issue. If you plan on doing this with the engine out of the water by hand by all means remove the spark plug wires from the spark plugs!!!

 

[Fishon72]

Thanks for the response! That puts my mind at ease, those gears are not cheap!

 

[RaisedByWolves]

Pappy, what about the clutch dog?

Same difference, but maybe the gears themselves are salvageable?

 

[Pappy]

Clutch dog can be checked by simply running the engine at the rpm and load the issue occurs at.
If the clutch dog is slipping out of gear it usually stays out. You can either watch or put your hand on the shift handle and feel it.
That's a valid test to make though.

 

[MrGiggles]

My experience with a shift dog that was rounded off, it would just grind, wouldn't even go into gear.

In my case, both the dog and gears were trashed, a local machine shop was able to build up the gear dogs and mill them square again, saving the cost of a whole new gear set and the shimming process. The clutch dog was fairly inexpensive so I just purchased a new one. Been fine for two seasons now.

 

[Pappy]

Depends on the gearcase and shift arrangement. Majority of them will hold until the load exceeds the capability of the rounded off dog.
Also, remember that on the fast majority of small engines that there is some adjustment available to help keep them healthy.

 

[Fishon72]

Hello,

Sorry for the late follow up, finally got a chance to do a test run with the new prop and fresh gear oil. Motor ran like a top with zero issues, and the stainless prop I got which seems to be slightly larger than the old one added roughly 2.5 mph to my top speed, and the boat gets on plane almost immediately now. Never thought a prop could make such a difference on a small motor like that!

I appreciate everyone’s feedback on this!

-Jay